Electric switch operator



May 61,1958

c.' M. PAYNE ELECTRIC SWITCH OPERATOR Filed Feb. 5, 1956 /NL/N TUF@ C//ffod M Payne United States Patent D ELECTRIC SWITCH OPERATOR Clifford M. Payne, Portland, Greg., assigner to Iron Fireman Manufacturing Company, Portland, Greg.

Application February 3, 1956, Serial No. 563,303

1 Claim. (Cl. 20G-138) This invention relates generally to condition responsive electric switches and more particularly to manual means applied to such a switch for rendering such a switch irresponsive to the condition.

In a preferred form in which the invention may be practiced and in which it is here illustrated and described by way of example only, the electric switch is the normally closed electric switch controlling the operation of the Warm air circulating fan of a so-called winter airconditioning system well known in the art.

In such a forced circulation warm air type of winter air conditioning system it is common to control the ow of circulating air with an electric motor driven air circulating fan, the air from the fan on its way to the space to be heated being directed to pass over a warm air furnace heated by an electrically driven automatic fuel burner controlled by a thermostat in the space to be heated. The most common type of control uses the space thermostat to start and stop the burner in accordance with the heat requirements of the space and uses a furnace limit control switch to open the burner motor circuit and stop the burner while for any reason the air leaving the furnace is above a pre-set temperature, usually 25l F. ln order not to circulate cold or drafty air before the burner has started it is common practice to provide the fan circuit with an air temperature controlled electric switch which will be normally closed to keep the fan in operation but which will be opened by its temperature sensitive control mechanism if the air temperature at the furnace goes down to a pre-set value, usually around 95 F.

The operation of such a winter air condition system is usually quite satisfactory for the part of the year when heat is required but experience has shown that in the part of the year when heat is not required it may also be desirable for greater living comfort to use the fan to circulate air through the house. To do this it has been the usual practice to oy-pass the air temperature controlled fan switch with another electric switch, usually called a summer fan switch, which can be manually operated to energize the fan motor even though the air temperature controlled fan switch is open.

ln thus providing a lay-pass switch for summer operation of the air circulating fan it has been necessary to install a separate switch either mounted in the enclosing case of the air temperature controlled fan switch or outside thereof and wire the manual switch in parallel with the automatic or temperature controlled switch.

To provide means having the full function of the bypass switch but requiring neither a switch nor the additional wiring, applicant has conceived of means for manually interrupting the control of the air temperature controlled fan switch by the temperature responsive operator with which it is equipped and thus leave the fan in operation. Following such conception applicant has invented and here discloses a novel and useful mechanism for the conceived purpose.

Applicants disclosure comprises the following descrip- 22,833,892 Patented May 6, 1958 rice tion referring to the attached drawing of a preferred form in which his invention may be practiced.

Referring now to the drawings there is shown in Fig. 1 a side view in partial section of what is basically a well known combination fan control and furnace limit switch now sold in large quantities in the United States. The view is taken along the line 1-1 of Fig. 2. It is to be noted that the protecting cover for the instrument has been removed in Figs. 1, 2, and 3.

Fig. 2 is a view in front elevation along the line 2-2 of Fig. 1.

Fig. 3 is an enlarged view along the line 3-3 of Fig. 1 and also is substantially an enlargement of a section of Fig. 2.

Fig. 4 is a view in partial section along the line 4-4 of Fig. 2.

Fig. 5 is a fragmentary sectional view along the lines 5-5 of Figs. 2 and 4.

Fig. 6 is a view in front elevation of the lower half of the protecting cover of the control illustrated.

Referring now to the drawings there is shown a frame 11 on which is supported by brackets 12 and 13 a first normally closed single pole, single throw electric switch 14 for controlling the air circulating fan motor of a winter air conditioning warm air furnace and a second normally closed, single pole single throw electric switch 15 for controlling operation of the burner motor of the furnace. Switches 14 and 15 respectively have operating plungers 16 and 17 which open the respective switches when they are sufficiently pressed thereinto.

Cylindrical guard 1S secured at one end to frame 11V encloses and protects axle rod 19 journalled at 20 in frame 11. Rod 19 at its other end is secured at 23 to bi-metal helix 21 whose other end is secured to guard 18 at 22. As normally applied the guard 18 extends through the furnace bonnet to position helix 21 in the warm air leaving the furnace. Helix 21 angularly positions rod 19 in response to the temperature of the warm air.

Journalled on dead shaft 24 secured on bracket 25 secured to frame 11 is a spool 28 secured to crank arm 26 to be rotated therewith by crank 27 secured to rod 19. Journalled on spool 28 are three cams 29, 30, 31 with indices adjacent dial 32 to indicate the temperatures of the warm air at which switches 14 and 15 will open and close. No complete description of the cam mechanism will be here given for it is old in the art and no part of this invention. Sutlice it to say that cam 29 is set with reference to dial 32 to determine the temperature at which both switches 14 and 15 will close while the position of cam 30 with respect to dial 32 determines the minimum temperature of the furnace air at which the fan motor will be energized and the position of cam 31 with respect to dial 32 determines the maximum temperature of the furnace air at which the burner motor will run.

Cam roller 33, journalled in the upper end of cam lever 34 as shown and pivoted at its lower end as shown in bracket 35 secured to switch bracket 13, is biased against cams 29 and 31 through switch operating plunger 17 by the closing mechanism of switch 15, not shown.

Similarly in the usual construction of the mechanism Without the modification of the present invention, cam roller 36 journalled in the upper end of cam lever 37 as shown and pivoted at its lower end as shown in bracket 3S secured to switch bracket 12, would be biased against cams 29 and 30 through switch operating plunger 16 by the closing mechanism of switch 14, not shown. But it should be particularly noted that the back of the U- section part of cam lever 37 has been cut away at 39 so that at no position of lever 37 could it rest against plunger 16 of switch 14 either to open switch 14 or hold it open. AThen' to make the operation of switch 14 responsive to air temperature it is seen that stili bar 40 is depressed at 39 to close the gap in lever 3'7 made at the-cutaway portion 39. .Bar 40 is held resiliently in position against lever`37 and plunger 16 of. switch 14 by lower resilientmember 41 secured at one end to bar 40 and with `its other endJpressing against bracket 13 of switcht15 and by upper resilient member. 42 secured at one end to bar 40 and at the other end to bracket 43 secured to lever'37 by screw 4'4. With 'this arrangementV and closure of the cutaway portion 39 of lever 37 switch 14 will be operated in response to furnace air temperature exactly as it would have been if lever 37 had not been cut away at 39.

.But vit is .by cutting away lever. 37 at 39 and llingthe gap--39 with resiliently supported bar 40'that this form of'the present invention is' practiced. Thus' when 'it is desired manually to prevent switch 14 from being opened and therefor to keep the fanY motor going regardless ofair temperature it is only necessary to movebar 40' away from lever 37 and switch stemv 16 so thatbar 40 can not follow lever 37 to move. plunger 16 to the openposition of switchr 14 when lever 37 ismoved by the temperature responsive cam mechanism towards its position of opening switch 14.

.In the presentexample the mechanism rfor moving'and retaining bar 40 away from Vlever 37 and switch stem 16 is shown to comprise a'molded nylon rod` 45 transversely slidably secured in bracket 46 secured to frame 11 by screws 47. Nylon rod 45 is seen to be' formed at one end with a rectangular extension 48 to be graspedV by the operators fingers and 'at the other end with a at topped, otherwise cylindrical, extension 49 for a positioning bar 40. Extension 49 is grooved to receive Cwasher 50. Rod '45 Ybetween its ends 48 and 49 has transversely formed thereonav rectangular plate 51 and a larger' rectangular plate`52. Plate 51 is transversely slidably. guided in a rectangular hole in bracket 46 and is resiliently held positioned therein by plate 52 and resilient finger washer 53 secured between C-washer 50 and bracket 46 asshown. It is seen, Fig. 3, that by moving rod 45 to the right'bar 40 is moved out of any possible contact with switch plunger 16 and switch 14 will remain closed at all times, but if rod 45 is moved to the left clear of bar 40 then bar 40 will follow lever 37 vand switch plunger 16 will be positioned by bar 40 to operate switch 14 in response to the ambient air temperatureV at bi-metalll. As va detail, indicated in Fig. 5,'part 52ofro`d'45 is formed with a smallpimple-likedetent 54 protruding from its side adjacent bracket 46 andbracket 46 is formed with a pair QII 4 of dimples 55 and 56 adapted to receive detent 54 respectively when rod is in the position of no interference with bar 40 or in its position of interference with bar 40.

As indicated in Fig. 6, cover 57 is for the purpose of combining with frame 11 to protect and cover switches 14 and 15 and their operating mechanism. Cover 57 is seen to have a rectangular hole 53 formed therethrough through which linger extension 48 of rod 45 extends and through which plate 52 is seen. At either end of hole position identification of rod 45 by its etect on switch operation is indicated by autdmeaning that switch 14 is temperature responsive or by man meaning that switch 14 will remain closed and the fan motor will run unless rod 45 is manually moved to the auto position.

Having thus stated a purpose for my invention, illustrated and described a novel and useful form in which myv invention may be practiced and explained its operation, I claim:

An electric switch apparatus comprisingin combination a hollow switch case having an open front, a cover for said front, a condition responsive cam including a earn 'stern and condition responsive means for rotating said stem, said cam being positioned in said case, a cam follower'lever biased into constant contact with said cam to position said lever in response to a condition, an electric switch in said case, means biasing said switch toward a closed circuit position, switch stem means operable to move said switch against said biasing means to an open circuit position, resilient lever means carried on said cam follower lever to overcome said irst biasing means and move said switch stern to the open position of said switch when said cam moves under` said cam follower to a preset position and post means slidably carried inside said cover for manual movement from the outside thereof when said cover is closed on said case to interpose said post in the path of said resilient lever to prevent said resilient lever from operating said switch stem to open said switch.

References Cited in the le of this patent UNITED STATES PATENTS 1,767,709 Smith Iune'24, 19.30 1,942,699 Henning Ian. 9, 1934 1,985,633 Finizie Dec. 25, 1934 2,157,857 Lee May 9, 1939 2,490,073 Malone Dec. 6, 1949 2,557,810 Bletz June 19, 1951 2,726,299 Carlson Dec. 6, 1955 2,759,068 Manecke Aug. 14, 1956 

